16.5 CHAPTER 16. OPTICAL PHENOMENA; PROPERTIES OF MATTER
Chapter 16 — Summary
See the summary presentation ( Presentation: VPqph at http://www.everythingscience.co.za)- Light of the correct frequency can eject electrons from a metal. This is called the
photoelectric effect. - A metal has a work function which is the minimum energy needed toemit an
electron from the metal. - Emission spectra are formed by glowing gases. The pattern of the spectra is
characteristic of the specific gas. - Absorption spectra areformed when certain frequencies of light are absorbed by
a material. - Lasers are devices thatproduce a special type of light that has many uses.
- Lasers have many uses,for example, in CD andDVD players, to cut material, in
surgery, in printing, in telecommunications and as laser pointers.
Chapter 16 End of Chapter Exercises
- What is the photoelectric effect?
- Calculate the energyof a photon of red light with a wavelength of
400 nm. - Will ultraviolet lightwith a wavelength of 990 nm be able to emit
electrons from a sheet of calcium with a work function of 2,9 eV? - What does the acronym LASER stand for?
- Name three types oflasers and their uses.
- Write a short essay onthe benefits lasers have had on modern society.
More practice video solutions or help at http://www.everythingscience.co.za(1.) 01n9 (2.) 01na (3.) 01nb (4.) 01nc (5.) 01nd (6.) 01ne